16406-48-7Relevant articles and documents
Photoreactions of the Triruthenium Cluster HRu3(CO)10(μ-COCH3). Isomerization of the Bridging Alkylidyne Ligand and Competing Ligand Substitutions
Friedman, Alan E.,Ford, Peter C.
, p. 551 - 558 (1989)
Irradiation of the title compound HRu3(CO)10(μ-COCH3) (A) in hydrocarbon solution under CO leads to the formation of the bridging μ,η2 acyl isomer HRu3(CO)10(μ,η2-C(O)CH3) (B).Quantum yields for isomerization φi were wavelength dependent ranging from CO 1.0 atm.In addition, over the range 0-1.0 atm, the φi values proved to be linearly dependent on PCO despite the absence of a stoichiometric requirement for CO in the isomerization.A key observation was that photoisomerization of A 13C labeled specifically at the bridging alkylidyne carbon, i.e., HRu3(CO)10(μ-13COCH3), gives B specifically labeled at the bridging acyl carbon, i.e., HRu3(CO)10(μ,η2-13C(O)CH3), with no evidence of scrambling of the label with other carbons in the complex.Photolysis in the presence of 13CO or other added ligands demonstrated the lability of the cluster coordinated carbonyls to photosubstitution reactions.The quantum yield for photosubstitution φs follows the same wavelength dependence as does φi, and it is proposed that the two processes result from competitive decay pathways of common intermediates.Limiting quantum yields for photosubstitution are about 0.25.A mechanism for these reactions related to that proposed previously for the photofragmentation of the parent triruthenium cluster Ru3(CO)12 is discussed.Prolonged 313-nm irradiation of HRu3(CO)10(μ,η2-C(O)CH3) under CO leads to cluster fragmentation and the formation of Ru(CO)5 plus acetaldehyde.
Allylic Amination of Unactivated Olefins by Nitroarenes, Catalyzed by Ruthenium Complexes. A Reaction Involving an Intermolecular C-H Functionalization
Ragaini, Fabio,Cenini, Sergio,Tollari, Stefano,Tummolillo, Giovanni,Beltrami, Raffaella
, p. 928 - 942 (2008/10/08)
A reaction is reported, resulting in the allylic amination of an unactivated olefin, cyclohexene, by a nitroarene, catalyzed by Ru3(CO)12Ar-BIAN (Ar-BIAN = bis(arylimino)-acenaphthene), under CO pressure. The reaction involves an int
C-H bond-making and -breaking processes in heteronuclear monoazadienyl complexes: Reactivity of HFeRu(CO)5{RC=C(H)C(H)=N-iPr} toward CO
Beers, Olaf C. P.,Elsevier, Cornelis J.,Kooijman, Huub,Smeets, Wilberth J. J.,Spek, Anthony L.
, p. 3187 - 3198 (2008/10/08)
In the photochemically induced reaction of Ru2(CO)6{RC=C(H)CH2N-iPr} (1a, R = Ph; 1b, R = Me) with Fe2(CO)9 the heteronuclear complex HFeRu(CO)5{RC=C(H)C(H)=N-iPr} (5) is formed in 35 % yield. HRu2(CO)6{RC=C(H)C(H)=N-iPr} (4), which is prepared quantitatively by photolysis of H2Ru4(CO)8{RC=C(H)C(H)=N-iPr}2 under a CO atmosphere, can act as an intermediate in this reaction and is proposed to be formed from 1 by a β-H-elimination reaction. Complex 5 is most likely formed via oxidative addition of the Ru-H bond in 4 to a Fe(CO)4 fragment. Complex 5 reacts with CO at 293 K to give reductive elimination of the monoazadiene ligand and formation of Fe(CO)5/Ru3(CO)12, probably via a mechanism involving opening of the hydride bridge. In the reaction of 5 with CO at 373 K the hydride is shifted to the monoazadienyl (MAD-yl) ligand, which is reduced from formally monoanionic to dianionic. In the case of R = Ph selective hydride transfer to Cβ is observed, resulting in the formation of FeRu(CO)6-{PhC(H)C(H)C(H)N-iPr} (6a), which features an unprecedented coordination mode of the MAD-yl ligand. For R = Me, both transfer to Cβ (affording 6b) and to Cim is observed, the latter affording FeRu(CO)6{MeC=C(H)CH2N-iPr} (7). This R-group dependence and also the difference in the reactivity of 5 and its homonuclear Ru2 analogue 2 is rationalized by the strength of the π-C=C coordination in the intermediate HFeRu(CO)6{RC=C(H)C(H)=N-iPr} (9). Complex 9a could not be prepared by the reaction of [FeRu(CO)6(PhC=C(H)C(H)=N-iPr}][BF4] (8a) with NaBH4, which afforded one diastereomer of FeRu(CO)6{PhCC(H)C(H)N-(H)-iPr} (10a), but 9a was formed by the conversion of 8a on silica. The X-ray crystal structures of 6a and 9a have been determined. Crystals of 6a are monoclinic, space group P21/c, with unit-cell dimensions a = 12.106(14) A?, b = 9.490(10) A?, c = 16.780(7) A?, β = 97.61(7)°, V = 1911(3) A?3, Z = 4, final R = 0.055, and Rw = 0.040 for 2215 reflections with I > 3.0σ(7) and 245 parameters. Crystals of 9a are orthorhombic, space group P212121, with a = 9.819(1) A?, b = 11.928(1) A?, c = 17.338(1) A?, V = 2030.7(3) A?3, Z = 4, and final R = 0.044 for 1434 reflections with I > 2.5σ(7) and 254 parameters. The most important conclusion of this work is that isostructural FeRu- and Ru2-MAD-yl complexes show a large difference in reactivity, which can be rationalized by stronger π-coordination of the MAD-yl ligand to Fe as compared to Ru.
Kinetics and mechanism of reductive elimination of hydrocarbons from (μ-H)3Ru3(μ3-CX)(CO)9 (X = Ph, Et, Cl, CO2Me, SEt, CHPhCH2Ph)
Duggan, Timothy P.,Golden, Matthew J.,Keister, Jerome B.
, p. 1656 - 1665 (2008/10/08)
The reaction of CO with (μ-H)3Ru3(μ3-CX)(CO)9 forms the corresponding CH3X (X = CO2Me, Ph, Et, CHPhCH2Ph) and Ru3(CO)12/Ru(CO)5; if β-hydrogens are present, alkenes and H4Ru4(CO)12 are also products. The rate law (X = Ph, Cl, and Et) is of the following form: rate = {kakcPCO/(kb + kcPCO)}[H3Ru3(CX)(CO)9] (X = Ph, ka = (6.4 ± 0.6) × 10-6 s-1, kb/kc = 0.49 ± 0.14 atm, 100°C; X = Cl, ka = (7.5 ± 0.7) × 10-5 s-1 and kb/kc = 3.5 ± 0.9 atm, 100°C; X = Et, ka = (7.6 ± 2.5) × 10-5 s-1, kb/kc = 14 ± 7 atm, 125°C). For X = CO2Me the rate law is zero order in PCO. Activation parameters for the limiting rate constant ka were determined (Ph, 35 atm, ΔH? = 131 ± 3 kJ/mol, ΔS? = 6 ± 8 J/(K mol); Cl, 35 atm, ΔH? = 125 ± 9 kJ/mol, ΔS? = 9 ± 25 J/(K mol); Et, 34 atm, ΔH? = 140 ± 19 kJ/mol, ΔS? = 22 ± 49 J/(K mol); CO2Me, 1 atm, ΔH? = 111.2 ± 1.3 kJ/mol, ΔS? = -0.8 ± 4 J/(K mol)). For X = Ph, Cl, and Et inverse deuterium isotope effects were measured (Ph, 86% d, kH/kD = 0.64 ± 0.08, 100°C, 35 atm; Cl, 85% d, kH/kD = 0.56 ± 0.06, 100°C, 6.8 atm; Et, 80% d, kH/kD = 0.46 ± 0.03, 100°C, 35 atm), but kH/kD = 1.01 ± 0.03 (95% d, 70°C, 1 atm) for X = CO2Me. The proposed mechanism involves a sequence of C-H reductive eliminations, each of which is preceded by reversible migration of hydrogen from Ru-H-Ru bridging to Ru-H-C bridging. The rate-determining step at high CO pressures is cleavage of the first Ru-H-C bond. For X = CO2R or SEt anchimeric assistance of the reductive elimination, perhaps through a species containing a (μ3-H)Ru2C interaction, is proposed.
Behaviour of Polynuclear Ruthenium Carbonyl Carboxylates in the Presence of Hydrogen and/or Carbon Monoxide
Frediani, Piero,Bianchi, Mario,Salvini, Antonella,Piacenti, Franco
, p. 3663 - 3668 (2007/10/02)
The thermal behaviour in the temperature range 293-453 K of n3)2>, n3)2> and n3)2> in hydrocarbon solution, taken separately or in binary mixtures, with each other or with m>, under nitrogen or, alternatively, hydrogen, carbon monoxide, or their mixtures, has been monitored by i.r. spectroscopy under reaction conditions.A deficiency of ligands leads to the formation of larger clusters while their abundance in solution shifts the equilibria towards mononuclear complexes.Under carbonmonoxide the formation of ruthenium(0) complexes is obtained from the above compounds.The presence of hydrogen together with carbon monoxide seems to facilitate such evolution of the system probably through the formation of intermediate hydridic derivatives which however were not detected.
Structural characterisation and properties of heteronuclear cluster 5-C5Me5)2Rh2Ru2(μ3-CO)2(CO)6>
Lindsell, W. Edward,McCullough, Kevin J.
, p. 425 - 432 (2007/10/02)
One of the three products of the reaction, earlier reported, between *Rh(CO)2> (Cp* = η5-C5Me5) and in toluene at 70 deg C in the presence of gaseous H2 has now been fully characterised as *2Rh2Ru2(μ3-CO)2(CO)6>.A single crystal X-ray diffraction study a 16.019(3), b 19.168(3), c 20.743(3) Angstroem; 2697 independent reflections with I > 3?(i); final R = 0.037, Rw = 0.050> has revealed a tetrahedral metal core with trply-bridging CO ligands on the two Rh2Ru faces.This structure is consistent with IR and 13C and 1H NMR spectra, alrhough the ion of highest mass in the FAB-mass spectrum is + formed by loss of CO from the parent cluster.The cluster is readily cleaved at ambient temperatures by reaction with CO or H2.
Photoreactions of the Triruthenium Cluster Ru3(CO)12 and Substituted Analogues
Desrosiers, Marc F.,Wink, David A.,Trautman, Ray,Friedman, Alan E.,Ford, Peter C.
, p. 1917 - 1927 (2007/10/02)
Reported is a comprehensive investigation of the medium, ligand, and wavelength effects on the quantum yields and flash photolysis kinetics for the photofragmentation and photosubstitution reactions of the trinuclear ruthenium cluster Ru3(CO)12.Also described are some related studies of the substituted clusters Ru3(CO)12-nLn (L =P(OCH3)3, PPh3, P(p-tolyl)3, or P(O(o-tolyl))3).These results are interpreted in terms of the following model for Ru3(CO)12 photochemistry.Photofragmentation (e.g.Ru3(CO)12 + 3L -> 3Ru(CO)4L) occurs predominantly from the lowest energy excited state and proceeds via an intermediate (I) isomeric to Ru3(CO)12 but not a diradical.I is proposed to have one coordinatively unsaturated ruthenium center trapable by a two-electron donor, i.e., L, to give a second intermediate Ru3(CO)12L which is the precursor to the photofragmentation products.Kinetic flash photolysis observations demonstrate that the lifetime of the latter intermediate is markedly dependent on the nature of L.Photosubstitution reactions (e.g., Ru3(CO)12 + L -> Ru3(CO)11L + CO) are proposed to occur largely from higher energy excited states via CO dissociation to give the unsaturated intermediate Ru3(CO)11, and flash photolysis studies establish the reactivity of this species with various L to follow the order CO > P(OCH3)3 > PPh3.
Hydrogenation of trimetallic clusters of the iron triad containing bridging carbyne ligands. Reductive cleavage of a triply bridging carbyne
Keister, Jerome B.,Payne, Martin W.,Muscatella, Michael J.
, p. 219 - 225 (2008/10/08)
The clusters HM3(μ-COMe)(CO)10 (1) (a, M = Fe; b, M = Ru; c, M = Os), prepared by methylation of the corresponding HM3(μ-CO)(CO)10 monoanion, react with hydrogen to give H3M3(μ3-COMe)(CO)9 (2). This process may be reversed under carbon monoxide. For these and other related carbyne-containing clusters the relative stabilities of HM3(μ-CX)(CO)10-nLn and H3M3(μ3-CX)(CO9-nLn are found to depend upon (i) the metal, (ii) the carbyne substituent X, and (iii) the ligands L. Thus, although 2a is unstable under ambient conditions, reverting nearly quantitatively to 1a, the substituted derivative H3Fe3(μ3-COMe)(CO)7(SbPh 3)2 (5a) can be isolated in fair yield by hydrogenation of 1a in the presence of triphenylantimony. Similarly, although HRu3(μ-CN(Me)CH2Ph)(CO)10 (4) does not react with hydrogen to give a stable product, in the presence of 4 equiv of triphenylantimony H3Ru3(μ3-CN(Me)CH2Ph)(CO) 6-(SbPh3)3 (6) can be prepared in good yield. These observations are rationalized in terms of the relative importance of M3-CX and C-X π-bonding interactions and the relative metal-carbonyl and metal-hydrogen bond strengths. Under more severe conditions reductive cleavage of the carbyne ligand as CH3X can be achieved. At 130°C and 3.5 MPa of 1:1 carbon monoxide-hydrogen, 2b decomposes to dimethyl ether and Ru3(CO)12. This process represents overall reduction of a carbonyl ligand by molecular hydrogen and is made possible by the activation of this carbonyl by methylation. The trends observed for cluster hydrogenation may have implications for potential Lewis acid activation of cluster-bound carbonyl ligands.
A High-pressure Infrared Study of the Stability of Some Ruthenium and Osmium Clusters to CO and H2 under Pressure
Nicholls, J. Nicola,Farrar, David H.,Jackson, Peter F.,Johnson, Brian F. G.,Lewis, Jack
, p. 1395 - 1400 (2007/10/02)
A high-pressure i.r. study has been made of the stability of some high-nuclearity carbonyl clusters of ruthenium and osmium to carbon monoxide and hydrogen, and of the thermal stabilities of theses clusters under an inert atmosphere.In solution, the hexanuclear cluster reacts with CO (90 atm, 160 deg C, 1 h) to produce the new pentanuclear cluster and .In contrast, in the solid state adds 2 mol of CO to form .The pentanuclear carbonyl undergoes reaction with CO to give both and , and with to give .On heating in an inert atmosphere loses CO to generate .This reaction is reversible.Reaction of , , , or with H2 under moderate pressure and temperatures gives and OsH2(CO)4>; first produces and proceeds to the same pruducts.On carbonylation under pressure yields , and gives a mixture of and .Pyrolysis of under argon at 120 deg C gives the hexanuclear carbide in high yield.
